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Searchpedia SEO field notes Callum Bennett Callum

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SEO Pictures

SEO pictures are website images optimized so search engines can understand, index, and potentially rank them while also improving page speed and user experience.

Beginner3 min readUpdated 2026-07-27Notes by Callum Bennett

What I’d do first

  • Rename files and write descriptive alt text for every content image.
  • Compress and resize images before uploading — aim for under 100KB.
  • Use srcset to serve the right size for each device.
  • Include images in your sitemap for better discovery.
  • Avoid keyword stuffing and generic filenames.

I used to think image SEO was just about alt text. Turns out, that's only the start.

What I'd do first

  • Rename your image files before uploading. red-leather-chair.jpg beats IMG_4923.jpg every time.
  • Write alt text that describes what's in the image and its purpose on the page. Think: "Woman smiling while using laptop in coffee shop" not "laptop coffee shop woman."
  • Compress and resize to the dimensions you'll actually display. A 4000px-wide photo at 5MB slows everything down.
  • Serve responsive images using srcset so mobile users don't download desktop-sized files.
  • Add images to your sitemap — especially if they're loaded via JavaScript or hidden behind tabs.

The path I'd take

  1. Audit your current images — check file sizes, dimensions, alt text, and filenames. Tools like Screaming Frog or Google Search Console's image report help.
  2. Fix filenames and alt text for all content images. Keep alt text under 125 characters and natural.
  3. Compress every image using a tool like TinyPNG or Squoosh. Aim for under 100KB for standard blog images.
  4. Implement responsive images with srcset and sizes attributes. This is non-negotiable for Core Web Vitals.
  5. Add images to your XML sitemap — or create a dedicated image sitemap if you have lots of them.
  6. Monitor performance in Search Console's image report and your page speed tools.

Watch-outs

  • Don't keyword-stuff alt text. Google reads it for context, but it's primarily for accessibility. "Red leather office chair for sale buy now" is bad. "Red leather office chair" is fine.
  • Avoid generic filenames like image1.jpg or photo.png. They tell search engines nothing.
  • Don't rely on CSS scaling to resize images. The browser still downloads the full file. Resize before uploading.
  • Don't use background-image for content images. Use <img> with alt text so search engines can index them.
  • Don't skip lazy loading for images below the fold — but make sure they're still crawlable.

What I got wrong

  • I used to stuff keywords into alt text thinking it would help rankings. It didn't — and it made my images less accessible.
  • I uploaded full-resolution photos and let CSS shrink them. My page speed was terrible until I started resizing and compressing first.
  • I ignored image sitemaps entirely. Once I added them, Google discovered images I didn't even know were missing from the index.

Next step

Alt TextMaster writing alt text that helps accessibility and SEO.

Quick answers

What are the best practices for image SEO?

Use descriptive filenames, write natural alt text, compress images, serve responsive sizes, and include images in sitemaps.

Should I use background-image or img tag for SEO?

Use the img tag with alt text for content images; background-image is for decorative purposes and is not indexed by search engines.

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Sources

Notes from Callum Bennett.